Automatic igniter for grenades



Oct. 27, 1936. c. G. PE1-TER AUTOMATIC IGNITER FOR `GRENDES Filed Jan. 26, 1955 lNveNTon: CHHRLES Gnamae. PET-ren WQQW HTTOR NEY.

Patented Oct. 27, 1936 PATENT OFFICE AUTOMATIC IGNITER FOR GRENADES Charles Gabriel Petter, Paris, France, assigner to Societe AlsaciennedExplosifs, (Societe Responsabilit Limite) Rhin), France Richwiller (Haut- Application January 26, 1935, Serial No. 3,539 In France February 6, 1934 1 Claim.

\ This invention relates to an automatic igniter for grenades, of the known type in which the match or safety fuse, which produces the explosion of'a fulminate detonator, is ignited by the shock on a primer, of a striker released when a releasing lever is acted upon.

Igniters of this type comprise two distinct parts:

A cap which is screwed in a screw-threaded hole of the grenade and supports the percussion mechanism and the releasing lever.

lA tube securedto the lower part of the cap and containinglthe safety fuse, and at the free end of which the detonator is beaded.

`The simple or double primer igniting the safety fuse is either arranged in a recess of the cap at the inlet of the safety fuse, or carried by a movable body of the percussion mechanism which is located outside the tube. In the first case, the striker is arranged in the recess receiving the primers and released by pulling off a locking member passing, with slight friction, through a thick metal wall obturating the said recess. In the second case,the primer is secured to a movable percussion pellet guided in the head of the igniter and which, when it is released by the releasing lever, strikes upon` a fixed needle or striker protecting the end of the safety fuse, but perforated in order that the primer can ignite the safety 36 fuse.

Both of these arrangements have the serious inconvenience of rendering difficult the protection of the primer and the safety fuse against atmospheric moisture. The arrangement of fluid- 35 tight packings constituted by .greased leather m'embers or by rubber members is precarious, owing to the fact that these materials become rapidly worn.

Besides in known igniters, the detonator is o connected to the safety fuse by a beaded part 55 iences.

50 known igniters, all the parts of the mechanism being, after assemblage, concealed by the releasing lever or enclosed in the body of the igniter.

The igniter forming the subject-matter of the present invention is free from these inconven- It is mainly characterized:

1-By the fact that the recess provided at the inlet of the safety fuse and which solely contains the igniting primer, is obturated in a fluid-tight manner by a metal sheet which can be perforated by a striker, all the elements of the mechanism of the latter being located outside said metal sheet.

2-By the fact that the safety fuse and the detonator are arranged within a Huid-tight sheath, this preventing any possibility of the burning composition becoming deteriorated by the fatty bodies encasing the explosive and by atmospheric moisture in case the igniters are stored separately from the grenades.

3-2By the fact that the control of the correct assemblage of the percussion mechanism is rendered easy by the arrangement of the members of the mechanism.

The detail features of the invention are set forth in the description given hereinafter which relates to a form of construction illustrated, by way of example only, in the accompanying drawing, in which:

Fig. 1 is a general elevation, with partial axial section, of an igniter according to the invention.

Fig. 2 is a partial cross section made according to line A-A of Fig. l.

Fig. 3 is an underside plan View, on an enlarged scale, of the striker shown separately.

Fig. 4 is a partial elevation corresponding to Fig. 3.

'Ihe igniter comprises a head or cap l, provided with a screw-threaded tubular part 2, and with a flange 3. In the screw-threaded tubular part 2 is secured the entire pyrotechnical part of the igniter.

'I'his pyrotechnical part is entirely contained in a metal tube 4, pressed out in one piece with its bottom 5 and which exactly fits, at its upper portion, into the bore of a securing ring 6. The latter is provided, at its upper part, with an annular seat 'l for the flanged edge 8 of the tube 4 held, after charging and placing in position, by a disc 9 made of a malleable metal such as tin for instance, clamped between a seat l0 of the head and the upper part of the ring 6 firmly secured by beading of a lower edge Il forming an extension of the screw-threaded part 2. Preferably, waxed joints are provided at I2 and I3. It will be seen that the contents of the tube 4 are absolutely protected, in a durable manner, against any contact with the atmosphere, against inltrations of water or other liquids, and against the impregnation of the priming powder of the safety fuse by the fatty material encasing some explosives.

'I'he so-called central tube 4 receives a unit constituted by a burning tube I4 containing the burning composition I5 held at both its ends by two conical plugs I6 formed of a paste of priming powder. On a certain portion of its length, the burning tube I4 has its wall reduced in thickness in order that said tube I4 may fit into another tube I'I closed at its lower part I8 and containing, from bottom to top, a charge of picric acid I9 and a fulminate cap 20, the whole constituting the detonator held between the bottom 5 of the central tube and the lower end of the burning tube I4 by washers 2| and 22, made of felt or equivalent material. The washer 22 is centrally perforated, as well as the bottom of the cap 20, for obtaining the explosion of the detonators through the combustion of the safety fuse I5.

The burning tube I4 receives, at its upper end,`

another retaining washer 23, centrally perforated and on which rests the primer 24 held by the disc 9; ensuring fluid-tightness.

The percussion and releasing mechanism which, according to an important feature of the invention is entirely located externally to the pyrotechnical part of the igniter, comprises a mushroom-shaped striker guided by its rod 26 in an axial conduit 2l of the head I and constantly vsubjected to the thrust of a spring 28 tensioned between the flange 29 and the bottom of the cylindrical recess 30 provided in the head I. The circular flange 29 of the striker has a diameter corresponding to that of the recess 30 and largely cut away preferably at two diametrally opposed places 3|. On the lower face of the ange 29 is provided an axial projection 32 having a central point 33 recessed at its root portion at 34 for allowing it to positively perforate the primer 24 Without the beaded frame 25 of the latter forming a retaining abutment on the edge of the projection'32.

The striker is locked, when the spring 28 is compressed to the maximum extent, by the releasing lever 35. The latter is made of pressed sheet metal and its upper part has two cheek members 36 bent down and stayed by a small metal plate 31 (Fig. 2) secured by electric welding at a few points, or otherwise. A pin 38 is transversely secured to the upper part of the lever and its ends, outwardly projecting relatively to the latter,^rest in two grooves 39 provided in two fork members 4i] arranged on either side of a diametral slot 4I of the head I. 'I'he two ends 42 of the cheek members 36 of the lever enter the slot 4I and, allowing the projection 32 of the striker to pass between them, bear on the flange 29 of the said striker which is pushed back by tensioning the spring when the lever is bent down along the grenade body 43, as shown in the drawing. The lever 35 is locked in this position by a pin 44, the stem of which passes both through the perforations 45 provided in the fork members and through the lever 35 and the stay member 31. This pin is not different from those used on known grenades and, for this reason, it has not been illustrated in the drawing.

The conduit 21 opens on the upper face of the head I, so that the end of the rod 26 is always visible. When it comes level with the face 46, the percussion mechanism is in working order and ready to be released. This feature, which is advantageous in that it allows a control at a glance, is peculiar to the present invention.

The operation of the igniter is as follows:

The grenade is primed, in the known manner by screwing the screw-threaded part 2 in the corresponding screw-threaded hole of the grenade body.

For ensuring the percussion of the grenade before throwing it, the grenadier holds tightly in his hand the grenade body 43 and the free end of the lever 35. He removes the pin 44 and throws the grenade. As soon as the lever 35 is released, the thrust of the spring 38 actuates the striker which ejects the lever 35 and the point 33 passes through the disc 9 and the primer 24. According to the invention, the combustion gases of the safety fuse easily find an issue to the exterior through the grooves 3I of the flange and th-e slot 4I of the head I.

The invention is not limited to the form of construction herein described and illustrated. It includes in its scope all means or combination of means suitable for carrying out the features set forth and in order to obtain the effects or results indicated.

What I claim as my invention and desire to secure by Letters Patent isz- An igniter for grenades including a casing for a firing mechanism having its lower end open and internally enlarged to provide a downwardly facing shoulder between the enlarged portion and the portion thereabove, a perforable closure disc resting against said shoulder, a securing ring mounted in said lower end and bearing against the peripheral portion of the disc, a tubular fuse casing fitting in said ring and having its upper end flanged outwardly to rest on the ring, a bead on the lower end of said first casing engaging the lower end of the ring to hold the latter in place, a. fuse tube fitted in the fuse casing in spaced relation to said disc, a fuse composition in said tube, a percussion cap resting on the upper end of the fuse tube and covered by said disc, and a detonator at the lower end of said fuse tube and within the fuse casing.

CHARLES GABRIEL PETTER. 

